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physiology exam #1 > The Membrane Potential > Flashcards

The Membrane Potential Flashcards

1
Q

Know what a dendrite, axon, axon hillock, soma, and synaptic cleft are.

A

Do it.

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2
Q

What is a coulomb a measure of?

A

Electrical charge (charge transported by 1 Amp for 1 sec)

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3
Q

Coulombs of a proton?

A

1x10(-19) C

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4
Q

What is Avagadro’s #?

A

Molecules in a substance

6.022 x 10(23)

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5
Q

What is Faraday’s Constant?

A

Charge on a mole of any monovalent ion

Coulombs X Avagadro

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6
Q

What is voltage a measure of?

A 
Potential Difference (E)
Work required to move a unit of charge from one point to another
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7
Q

What is current?

A

Current is the net flow of charge. It is measured in amperes (C/sec).

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8
Q

What is resistance?

A

Measure of the ease with which a current flows
Measured in Ohms
E/I

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9
Q

What is conductance? Measurement?

A

Reciprocal of Resistance (I/E)

Siemens

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10
Q

Relative levels of Na, K, and Cl inside the cell (rather than outside the cell)

A

High K+ in cell

Low Na and Cl inside

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11
Q

What do ions pass through in a cells?

A

ion specific channels

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12
Q

What is the ionic equilibrium potential?

A

An electrical potential difference across the membrane caused by the selective permeability/ionic gradients of the cell membrane.

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13
Q

The thin membrane facilitates what occurance when positive ions leave the cell.

A

Attraction of negative ions to the opposite side of the membrane.

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14
Q

Is most of the cellular fluid chargeD?

A

No

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15
Q

T or F. Equilibrium is established when there is no net ion movement across the cell membrane.

A

True

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16
Q

What influences the rate of flow of an ion across a PM?

A

Concentration Gradient
Voltage Difference
Conductance of Ion Channels

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17
Q

What is the Nernst equation used for?

A

Determines the equilibrium potential for a single ion

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18
Q

What is the Nernst equation?

A

E = [(58mV)/z] x log [(outside ion conc)/(inside ion conc)]

19
Q

When would you use 61 instead of 58?

A

Body temp (instead of RT)

20
Q

What does the principle of electrical neutrality state?

A

Under biological conditions, the bulk concentrations of cations and anions in a compartment are equal.

21
Q

What is Donnan Equilibrium a study of?

A

It shows how the electrical potential across a membrane must balance the conc gradients or K and Cl.

22
Q

What is the Donnan Equilibrium equation?

A

[(Kout)(Clout)] = [(Kin)(Clin)]

23
Q

The Na/K+ pump burns up # ____, pumps out # _______ and takes in # ________.

A

1 ATP
3 Na
2 K

24
Q

What is the Goldman Equation?

A

The nernst equation, but for multiple ions at once.

25
Q

What does the Goldman equation take into account?

A

Concentration gradients of different ions and relative permeability of the membrane

26
Q

What is the Goldman equation?

A

See page 1-7 (pain to type in)

27
Q

Ratio of Pk:PCl:PNa

A

1: 0.45: 0.02

28
Q

Name three properties that are responsible for maintenance of the transmembrane potential

A

Transmembrane Resistance (Resting)
Axial Resistance
Membrane Capacitance

29
Q

What is input resistance? the equation?

A

relationship btw current injected and change in mem pot.

= (change in V) / I

30
Q

What determines input resistance?

A

of ion channels

31
Q

What is the specific membrane resistance?

A

The resistance of a unit area of membrane

32
Q

Input resistance formula using specific mem. resistance

A

=Rm/(4pir(2))

33
Q

The greater the area of a cell, the ____ its resistance.

A

Lower

34
Q

A neuron smaller neuron fires faster than a larger one because…

A

(With constant current) the small neuron’s higher resistance will cause a higher E

35
Q

What is the relationship of membrane resistance and axial resistance to a subthreshold potential value moving down an axon

A

High Mem. Res = Father Distance Traveled

High Axial Res = Shorted Distance Traveled

36
Q

What is lambda?

A

The length constant, distance over which an electric potential decrements to 37% of peak value

37
Q

What is the equation of lambda?

A

= sq. rt (Rm/Ri)

38
Q

Larger Rm = ______ lambda

A

Larger

39
Q

Larger lambda increased likelihood of_______

A

summation

40
Q

What might the location of the synapse on a cell matter?

A

Different areas have diff #s of voltage dependent sodium channels

41
Q

Relationship between diameter and electronic speed?

A

Synaptic potential will e larger in a small dendritic process than a large one

Larger dendrite will spread farther

42
Q

What is the membrane time constant?

A

Time necessary for the electrotonic potential to decree to 37% of its original peak.

43
Q

Equation for membrane time constant?

A

(Membrane Resistance) (Membrane Capacitance)

44
Q

A larger tau means what for summation?

A

Better chance

physiology exam #1 (7 decks)

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